Preparation of isopropyl-para-aminophenol



Patented Sept. 29, 1925.,

UNITED STATES PATENT OFFICE.

' m E. BUG, OF BOSELLE, NEW JERSEY, ASSIGNOR TO STANDARD DEVELOPMENT COMPANY, A CORPORATION OF DEAWABE.

'PBIEEPABATION OF ISOPBOPYL-PA'BA-AMINOPHENOTI.

no Drawing.

To all whom it may concem:

Be it known that I, HYYM E. BUc, a citizen of the United States, residing at Roselle, in the county of Union and State of New Jersey, have invented a new and useful Improvement in the Preparation of Iso ropylara-Aminophenol, of which the 0 lowing is a specification. In accordance with the present invention, isopropylpara-aminophenol is produced in the following manner:

An isopropyl-halide, preferably isopropyl chloride, is mixed with a proximately equimolecular roporitions o para-aminophenol and the mixture heated in the presence of a non-reacting solvent, such as acetone or isopropyl alcohol. The heating is carried out in an autoclave, the reacting chemicals being maintained between 150 and 200 C.

for 6 to 10 hours, in which time the reaction is substantially complete. There is usually a slow rise in pressure during the heating. In case the pressure in the autoclave becomesexcessive, say over 300 pounds, the autoclave may be cooled, the pressure released, the autoclave again sealed and heating resumed.

As an example of the operation of the process 110 parts of para-aminophenol, j 80 partsof isopropyl chloride and 300 parts of lsopropyl alcohol (all by weight) may be employed. The proportion of isopropyl alcohol may be greater or less than that specifically name 7 within the limits of 200 to 600 parts.

After the reaction is completed the isopropyl-para-amino henol may be separated wit any unreacte -upon para-aminophenol or it ma be isolated and separately purified.

40 The initial separation and purification of the 7 mixed bases may suitably be efiected by treating the reaction mixture with an acid, such as hydrochloric or sulfuric acid, for example, with molal arts of HCl in the form of concentrated 37%) acid, adding decolorizin material such as decolorizing carbon or ers earth and filtering. To se arate the aminophenols, thesolution may su1tably be made alkaline, for example, with VNa,GO,, and extracted with ether. The

it ispreferred that it be Application filed. October 12, 1921. Serial No. 507,868-

' phenol may be effected in the following manner The filtered acid solution of mixed amino-phenols above described is treated with nitrous acid in approximately molecular proportion. The nitroso-compound formed by the 1sopropyl-para-aminophenol se arates out as a white, crystalline solid, solu 1e with dlfliculty in water, and is filtered out and washed. It may be reconverted to the ammo-phenol by reduction with strong HCl and stannous chloride, and the resulting isopropyl-para-aminophenol may be urified in any suitable manner; for examp e, by making the solution alkaline with Na CO, and extracting with ether. isopropyl-paraaminophenol is a white, crystalline compound, melting at 148-152 C. with some charring. .It ma readily be converted into a more soluble an t, for example, the sulfate, hydrochloride, etc. These salts of iso ropyl-para-aminophenol are white, crysta ine compounds, readil solublein water, and are highly desira 1e for use as photographic deve opers.

I cla1m:

1. The procw' of preparing iso ropylpara-aminophenol which comprises heating together isopropyl chloride and para-aminophenol.

2. The para-aminophenol which comprises sub ectmg isopropyl chloride and para-aminophenol together to heat in the presence of a nonreactilvfi solvent. f I l 3. 0 process. 0 preparing isopi'o ara-aminophenol which comprises subj eztmg isopropyl chloride and para-amino henol together to a tem C. in the presence 0 isopropyl alcohol. 4. The process of preparing isopropylpara-aminophenal which comprises sub ect- The purifiedrature of 150 to process of preparing isopropyl A phenol in the presence of a solvent andl sepamtimg phenol. v 8. As an article of manufacture, isopropyl-pam-aminophenol, a White crystallirio solid melting at 148 to 152 C. M

the resulting isopropyl-pam-amino- 

